The present invention relates to a method of treating fiber. More particularly, it relates to a method of treating fiber which comprises attaching a sublimable substance onto the fiber to increase the smoothness (or lubricity) and secondary processability thereof and furthermore to a method of treating fiber wherein the provision of smoothness (or lubricity) to fiber and a water-repellent, oil-repellent and stain-inhibiting treatment are performed at the same time.
Heretofore, in knitting or weaving fibers, or forming webs of nonwoven fabrics to produce various fiber products, the fibers have been treated with an oily lubricant, such as solid paraffin, Japan wax, carnauba wax, spindle oil, silicone oil, etc.
For example, in the production of knitted fabrics, spun knitting yarns have been provided with smoothness prior to the knitting by rubbing the surface of the yarn with solid lubricants, such as solid paraffin, Japan wax, carnauba wax, etc. in order to reduce the friction resistance between the yarns and knitting needles, and between adjacent yarns. In accordance with this method of treating yarns, however, the oily lubricant cannot be uniformly adhered to the yarns. Therefore, the tension is large and uneven, and may result in stoppage of the knitting machine. Furthermore, this method of treating yarns has the disadvantage that since the lubricant is a solid material and the yarn surface is rubbed with such solid materials, the fluff of the yarns first attaches onto the lubricant and then onto the yarns, producing unevenness in the diameter of the yarns and finally providing knitted fabrics which are non-uniform. Additionally, much labor is required to replace the used lubricant with a new one owing to the consumption thereof and in watching the condition of attachment of the fluff, and the treatment efficiency is poor because the yarn treatment is performed on individual yarns.
With weaving yarns, sizing has been applied to prevent the formation of fluff during the course of weaving and to increase the strength of the yarn. This sizing, however, decreases the smoothness of the yarn. Therefore, owing to friction between the yarn and the knitting stick during weaving, fluff is formed even in warp. This formation of fluff decreases the shedding properties and lowers the yarn workability. Furthermore, fabrics of uniform quality cannot be obtained.
In order to eliminate the disadvantages described hereinbefore, weaving yarns have been treated with a lubricant prepared by emulsifying waxes with a surface active agent, or they have been coated with a silicone-based lubricant by spraying. The wax type lubricant suffers from the disadvantage that it is oxidized in air and difficulties are encountered in completely removing the oxidized product by post-treatment as with the silicone-based lubricant.
The thus-treated fibers are processed by knitting, weaving, formation of webs, etc. to provide fiber products. After the formation of such fiber products, the lubricant used in the preceding stage is useless. The lubricant should be removed by the use of caustic soda or a surface active agent. For this operation, additional steps and equipment are undesirably required. Even by application of such additional operations, it is impossible to completely remove the lubricant. The residual lubricant causes trouble at subsequent operations, such as post-dyeing, etc. and makes it difficult to obtain a fiber product of high quality. In various resin treatments, for example, water-repellency, oil-repellency and stain-inhibiting finishing using a fluoride compound, the presence of residual lubricant markedly reduces the finishing efficiency and causes various difficulties.
It is an object of the present invention to provide a method of treating fiber which imparts lubricity (or smoothness) uniformly to the fiber with high workability.
Another object of the present invention is to provide a method of treating fiber wherein provision of a lubricity treatment and a treatment to impart water-repellency, oil-repellency, and stain-inhibiting properties by the use of a fluorine compound are preformed at the same time.